Joysticks may be used as an input means for a wide variety of control devices. Conventionally, a joystick is mounted in or on a user input or control device in such a way as to allow movement of the joystick, where the joystick movement is interpreted by the control device as a command regarding a controlled object, e.g., in a game application. The object may be a physical object, such as a remote controlled car or plane, or a graphical representation of an object, such as a cursor on a computer display.
Typically, the movement of the joystick is a physical displacement or a deflection away from a center, or resting, position. The displacement of the joystick is registered by the control device, which executes a function with regard to the controlled object according to the input indicated by the joystick position. Often the joystick controls a motion of the object, specifically, a velocity of the object. The direction of the joystick deflection from the center position indicates a commanded direction of motion for the object, while the magnitude (e.g., angle of deflection) controls the rate at which the object is commanded to move.
Conventionally, a joystick includes one or more springs that operate to return the joystick to its resting position when the joystick is released from a deflected position. However, due to friction forces within the control device, the joystick may not consistently return to a centered, or rest, position—or it may do so only after a substantial passage of time. This can make it unclear if a small deflection of the joystick from the center position is due to friction forces preventing the joystick from returning to the center, or if instead a user is purposefully causing the small deflection in the joystick position. For this reason, a region around the center position is often designated wherein a deflection of the joystick is ignored, a so-called “dead band,” which establishes a threshold joystick deflection necessary to register with the control device and to control an object. Further, the joystick input may be limited to only one function regarding the controlled object.
Another disadvantage of a conventional joystick is that it is basically a relative position control interface and sometimes the user needs an absolute position control interface.